Browsing by Author "Derrick Adriko"

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    Investigating the Use of Density Polyethylene in Modifying Bitumen to Improve Performance of Flexible Pavements Along Climbing Lanes
    (Uganda Christian University, 2024-04-13) Derrick Adriko
    This study investigated the application of bitumen modification in improving the performance of flexible pavements against rutting along climbing lanes. Such sections are characterized as severely loaded sites that experience deceleration of traffic and increased loading time. As the pavement temperature increases, the binder softens and is unable to withstand the increased loading hence causing shear deformation. A case study was evaluated at the climbing lane section along Bweyogerere – Jinja road that experienced premature deformation a few years after its reconstruction. The study deduced that the failure was caused by instability rutting within the asphalt layer. The properties of both aggregates and bitumen were evaluated to understand the cause of failure. The study employed mechanistic – empirical approach where the index properties of the materials were related to pavement performance using recommended asphalt models. Whereas the aggregates were found to possess excellent performance, the bitumen was found to be temperature sensitive hence causing reduced stiffness at high temperatures. Bitumen modification with LLDPE showed reduction in temperature susceptibility and increased stiffness modulus at high service operating temperatures and loading time. Asphalt mix specimen with 2% LLDPE increased the resistance to permanent deformation without affecting pavement durability. The modified specimen were subjected to ITS and PRD tests where an increase in tensile strength of 16.7% was recorded. The air voids at refusal density increased by 42% signifying increased flexibility upon secondary compaction under heavy loads thereby increasing service time and solving the issue of premature deformation.
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    Investigating the Use of Linear Low-Density Polyethylene in Modifying Bitumen to Improve the Performance of Flexible Pavements Along Climbing Lanes
    (2024-04-16) Derrick Adriko
    This study examined the concept of bitumen modification to improve the performance of flexible pavements against rutting on climbing lanes. Such sections are subjected to slow moving heavy traffic and prolonged loading time hence categorized as severely loaded sections. As pavement temperatures rise, the asphalt binder softens and is unable to withstand the loads, leading to deformation. A case study along Bweyogerere – Jinja road climbing lane revealed premature deterioration in form of instability rutting in the asphalt layer. Using mechanistic and empirical approaches, aggregates and bitumen were evaluated to understand the failure. While aggregates showed good performance, the bitumen susceptible to temperature variations which reduced stiffness at high temperatures. Modifying bitumen with 2% LLDPE reduced the temperature susceptibility and increased the stiffness modulus which showed improved resistance to permanent deformation without compromising durability of the asphalt mixture as portrayed from Marshall test results. The modified specimens exhibited a 16.7% increase in tensile strength and a 42% increase in air voids at refusal density signifying increased flexibility under heavy loads and extending service life thereby addressing premature deformation issues at the road section.